Xu et al. SpringerPlus (2016) 5:1118 DOI 10.1186/s40064-016-2818-9
Open Access
RESEARCH
Cross‑cultural adaptation and validation of the Chinese version of Toronto Extremity Salvage Score for patients with extremity sarcoma Leilei Xu, Minghui Sun, Weixiang Sun, Xiaodong Qin, Zezhang Zhu and Shoufeng Wang*
Abstract Objective: As a widely used instrument for patients with extremity sarcoma, the Toronto Extremity Salvage Score (TESS) has never been cross-culturally adapted for Chinese population. The objective of our study was to investigate the comprehensibility, reliability and validity of the Chinese version of TESS for use in patients with extremity sarcoma. Methods: A consensus version of the Chinese TESS was developed under the review of a committee according to international guidelines. 64 patients were recruited to complete the Chinese TESS, the Musculoskeletal Tumor Society (MSTS) Rating Scale, and the Quality of Life Questionnaire Core 30 (QLQ-C30). Reliability was assessed using the intra-class correlation coefficient (ICC) and Cronbach’s α. Validity was assessed with Pearson’s correlation between the similar domains of the two questionnaires. Results: The ICCs for the test–retest reliability was 0.932 for the upper extremity questionnaire and 0.893 for lower extremity questionnaire, respectively. The Cronbach’s α was 0.953 for the lower extremity questionnaire and 0.921 for the upper extremity questionnaire, respectively. Convergent validity of the TESS based on Pearson correlation coefficients indicated significantly moderate to high correlations between the TESS and the MSTS as well as the QLQ-C30, with r ranging from 0.535 to 0.782. Conclusions: The Chinese TESS is a comprehensible, reliable, and valid instrument that can be utilized for future cross-cultural international studies of extremity sarcoma. Keywords: TESS, Chinese, Extremity sarcoma, Function Background Sarcoma is a rare type of cancer that represents approximately 1 % of all newly diagnosed cancers (Borden et al. 2003). Due to the significant impact of extremity sarcoma surgery on the patients’ function, health related quality of life (HRQoL) is now recognized as an important outcome measure of the surgery (Hoffmann et al. 2006; Griesser et al. 2012; Ruggieri et al. 2011). Development of instruments to measure HRQoL is essential to determine *Correspondence: [email protected] Department of Orthopedic Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road 321, Nanjing 210008, China
patients’ perceived physical and mental health (Schreiber et al. 2006; Lopez-Guerra et al. 2011). To be noted, patients with sarcoma may have a significant heterogeneity regarding tumor type, reconstructive techniques and the extent of tissue excised during surgery. Therefore, it is important to develop an instrument that takes heterogeneity into account when measuring functional outcome. And a disease-specific measure rather than a generic measure is preferred for the proper assessment of physical function in patients with extremity sarcoma. To date, several disease-specific questionnaires have already been developed to evaluate functional outcomes for patients undergoing surgery for extremity sarcomas (Davis et al. 1996; Enneking et al. 1993; Bekkering et al.
© 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Xu et al. SpringerPlus (2016) 5:1118
2009). Some examiner-dependent clinical measures such as range of motion and muscle strength or a combination of symptoms and mobility have been used. However, measures that reflect the patient’s perception seems more desirable in clinical practice. As a patient-completed questionnaire that takes into account the heterogeneity of sarcomas, the Toronto Extremity Salvage Score (TESS) was developed for assessing physical function of patients undergoing surgery for extremity sarcoma (Davis et al. 1996). The TESS questionnaire is a disease-specific and selfadministered questionnaire based on the definitions of disability, impairment, and handicap as documented by the World Health Organization (Davis et al. 1996). The content of the TESS includes the types of functional difficulties experienced by extremity sarcoma patients, such as body movement, mobility, self-care, and performing daily tasks. To date, several studies have reported the validation of the TESS in a Portuguese (Saraiva et al. 2008), Danish (Saebye et al. 2014), Korean (Kim et al. 2015) and Japanese version (Ogura et al. 2015), yielding good test– retest reliability and internal consistency. However, to the best of our knowledge, there is no study that addresses the application of TESS to patients from the Chinese population. Herein, this study was conducted to investigate the comprehensibility, reliability and validity of the Chinese version of TESS for use in patients with extremity sarcoma.
Methods Subjects recruitment
The protocol of recruitment of participants was approved by the ethics committee of the hospital. Patients who visited our clinic center between March 2011 and September 2014 were prospectively evaluated for the eligibility of recruitment in this study. The following inclusion criteria were used: (1) aged more than 18 years; (2) at least 1 year after curative surgery for histologically confirmed extremity sarcoma; (3) without local recurrence, distant metastasis or complications related to surgery. Finally, 64 patients including 35 male and 29 female participated in the study and gave their informed consent. Demographic data were collected from the medical records, including patients’ age, gender, location of the tumor, histological type, type of surgery and period of follow-up. Translation and adaptation of the TESS
The translation and adaptation processes of the TESS were performed according to the guidelines used by previous literatures (Saraiva et al. 2008; Kim et al. 2015; Ogura et al. 2015). The English version of the TESS was translated into Chinese independently by three native Chinese bilingual translators who were familiar with the
Page 2 of 6
topic and the research concept. Subsequently, the two translators with the medical background analyzed and compared the three translations together with two senior musculoskeletal oncologists, and then combined them into one single translation. The consensus version was back translated into English independently by two bilingual translators who were kept blind to the procedures of the forward translation. All versions of the translation were analyzed by the expert committee, which was comprised of the 5 translators, one methodologist, and 2 orthopedic surgeons (X.L. and W.S.). The committee evaluated conceptual equivalence of all items and answers, and discrepancies between members were discussed. The pre-final version of the TESS was created after consensus was reached among the expert committee. In the pre-test step, 40 volunteers aged more than 18 years were recruited from the local community to test the pre-final Chinese version of the TESS. These volunteers were questioned about their understanding of the questionnaire items. Most of the items in the questionnaire could be correctly understood and answered by the volunteers. There was a high incidence of “not applicable” with regard to the question on sexual activity, which was therefore omitted from the questionnaire. After this process, the final version of the Chinese version of the TESS was developed. It consists of a lower extremity and an upper extremity version both with 29 questions. Each question is rated on 5-point scale, including “impossible to do,” “extremely difficult,” “moderately difficult,” “a little bit difficult,” and “not at all difficult”. The participant can select “not applicable” when the question is not a usual activity. The total score ranges from 0 to 100, with higher scores indicating better function. Reliability and validity test of the TESS
All the patients were asked to answer the TESS questionnaire at their follow-up visit after surgery. The time needed for the completion of the questionnaire was recorded for each participant. To examine the test– retest reliability, patients were asked to complete the same TESS questionnaire 1 week later. All the patients returned the second questionnaire used for analysis. The data were collected by an author (S.W.) who was kept blind of the patients’ diagnosis or treatment. To examine the convergent validity, the patients were also asked to complete the Musculoskeletal Tumor Society (MSTS) Rating Scale, and the Quality of Life Questionnaire Core 30 of European Organization for Research and Treatment of Cancer (EORTC QLQ-C30). The MSTS Rating Scale is a widely used functional score for patients with extremity sarcoma (Rebolledo et al. 2013). It consists of factors pertinent to the patient, including pain, function, emotional acceptance, use of any external support,
Xu et al. SpringerPlus (2016) 5:1118
walking ability, and gait alteration. A value of 0–5 points (maximum overall score, 30 points) was assigned to each of these factors. The QLQ-C30 is a 30-item questionnaire used to evaluate the function and QoL in cancer patients (Fitzsimmons et al. 1999). The following scales among the functional scales of QLQ-C30 were used in this study, including physical functioning (PF), role functioning (RF), social functioning (SF) and QoL. A high score on the functional scales represents a high level of QoL and a high level of functionality.
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Table 1 Baseline characteristics of the patients Characteristic
Patients (n = 64)
Age (year)
47.5 ± 15.2
Gender Male
35
Female
29
Time from surgery (year)
1.9 ± 1.2
Tumor location Upper extremity Upper arm
12
Factor analysis
Shoulder
5
Confirmatory factor analysis was carried out with each factor being specified to load on its subscale. Model fit was assessed with the following parameters, including the comparative fit index (CFI), the normed fit index (NFI), root-mean square error of approximation (RMSEA), and the 90 % confidence intervals (CIs) of RMSEA. A good fit of the model was indicated by ratios between the Chi square test and degrees of freedom less than 3, CFI and NFI values not less than 0.90, and RMSEA not more than 0.08.
Forearm/wrist
4
Elbow
2
Statistical analysis
SPSS for Windows version 16.0 statistical software (SPSS, Chicago, IL, USA) was used for statistical analyses. Descriptive demographic data and scores were reported as mean values ± standard deviation. The test–retest reliability was examined using intra-class correlation coefficient (ICC). The internal consistency was evaluated by Cronbach’s α, with a value >0.70 considered acceptable. To determine the convergent validity of the TESS, correlations between similar domains of the TESS and the QLQ-C30 or the MSTS were analyzed by Pearson correlation analysis. The correlation coefficient larger than 0.40 was considered to indicate adequate convergent validity.
Results The mean time used to complete the TESS questionnaire was 285.2 ± 75.7 s (range 182–382). The baseline characteristics of the patients were summarized in Table 1. The mean age at the time of completion of the questionnaire was 47.5 ± 15.2 years (range 18–68 years). The most common histological types were osteosarcoma (n = 15) and chondrosarcoma (n = 13) for bone sarcoma and liposarcoma (n = 11) for soft tissue sarcoma. Most patients received limb salvage surgery followed by chemotherapy with a mean follow-up of 1.9 ± 1.2 years (range 1–3 years). Results of reliability evaluation for Chinese version of the TESS were summarized in Table 2. The ICC for the test–retest reliability was 0.932 for the upper extremity
Lower extremity Thigh
14
Lower leg
10
Pelvis/hip
7
Knee
6
Ankle/foot
4
Histological type Bone Osteosarcoma
15
Chondrosarcoma
13
Soft tissue Liposarcoma
11
Undifferentiated pleomorphic sarcoma
6
Myxofibrosarcoma
5
Fibrosarcoma
4
Leiomyosarcoma
3
Epithelioid
3
Others
4
Surgery type Amputation
11
Limb salvage
53
questionnaires (95 % confidence interval (CI) = 0.745– 0.971) and 0.893 for lower extremity questionnaires (95 %CI = 0.755–0.937), respectively. In addition, the test for internal consistency showed strong reliability with a Cronbach’s α of 0.953 for the lower extremity questionnaire and 0.921 for the upper extremity questionnaire. The Pearson correlation coefficients between one item and the total score ranged from 0.533 to 0.869 for the lower extremity questionnaire and from 0.587 to 0.913 for the upper extremity questionnaire. As shown in Table 3, the overall mean score of the TESS was 87.6 ± 20.2 (range 40–100). The mean scores of the lower extremity questionnaire and the upper extremity questionnaire were 83.4 (range 40–100) and 92.3 (range 45–100), respectively. The mean score of the MSTS was 24.6 (range 5–30). The mean score of the QLQ-C30 was
Xu et al. SpringerPlus (2016) 5:1118
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Table 2 Reliability test of the simplified Chinese version of the TESS The TESS
ICC (95 % CI)a
Cronbach’s α
Correlationb
Lower extremity
0.893 (0.755–0.937)
0.953
0.533–0.869
Upper extremity
0.932 (0.745–0.971)
0.921
0.587–0.913
Table 4 Convergent validity of the Chinese TESS
MSTS Physical functioning Role functioning
ICC indicates Intraclass correlation coefficient; 95 % CI indicates 95 % confidential interval
Correlations between one item and the total score excluding that item using Spearman rank correlation coefficient
MSTSb
0.682†
0.782†
0.735†
†
0.547†
†
0.532†
†
0.635†
0.712
Quality of life †
TESS
0.637†
0.638
Social functioning
b
a
Upper extremity (r)
QLQ-C30
a
Table 3 Patients’ score of the TESS, the MSTS and the QLQC30
Lower extremity (r)
0.689
p
Open Access
RESEARCH
Cross‑cultural adaptation and validation of the Chinese version of Toronto Extremity Salvage Score for patients with extremity sarcoma Leilei Xu, Minghui Sun, Weixiang Sun, Xiaodong Qin, Zezhang Zhu and Shoufeng Wang*
Abstract Objective: As a widely used instrument for patients with extremity sarcoma, the Toronto Extremity Salvage Score (TESS) has never been cross-culturally adapted for Chinese population. The objective of our study was to investigate the comprehensibility, reliability and validity of the Chinese version of TESS for use in patients with extremity sarcoma. Methods: A consensus version of the Chinese TESS was developed under the review of a committee according to international guidelines. 64 patients were recruited to complete the Chinese TESS, the Musculoskeletal Tumor Society (MSTS) Rating Scale, and the Quality of Life Questionnaire Core 30 (QLQ-C30). Reliability was assessed using the intra-class correlation coefficient (ICC) and Cronbach’s α. Validity was assessed with Pearson’s correlation between the similar domains of the two questionnaires. Results: The ICCs for the test–retest reliability was 0.932 for the upper extremity questionnaire and 0.893 for lower extremity questionnaire, respectively. The Cronbach’s α was 0.953 for the lower extremity questionnaire and 0.921 for the upper extremity questionnaire, respectively. Convergent validity of the TESS based on Pearson correlation coefficients indicated significantly moderate to high correlations between the TESS and the MSTS as well as the QLQ-C30, with r ranging from 0.535 to 0.782. Conclusions: The Chinese TESS is a comprehensible, reliable, and valid instrument that can be utilized for future cross-cultural international studies of extremity sarcoma. Keywords: TESS, Chinese, Extremity sarcoma, Function Background Sarcoma is a rare type of cancer that represents approximately 1 % of all newly diagnosed cancers (Borden et al. 2003). Due to the significant impact of extremity sarcoma surgery on the patients’ function, health related quality of life (HRQoL) is now recognized as an important outcome measure of the surgery (Hoffmann et al. 2006; Griesser et al. 2012; Ruggieri et al. 2011). Development of instruments to measure HRQoL is essential to determine *Correspondence: [email protected] Department of Orthopedic Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road 321, Nanjing 210008, China
patients’ perceived physical and mental health (Schreiber et al. 2006; Lopez-Guerra et al. 2011). To be noted, patients with sarcoma may have a significant heterogeneity regarding tumor type, reconstructive techniques and the extent of tissue excised during surgery. Therefore, it is important to develop an instrument that takes heterogeneity into account when measuring functional outcome. And a disease-specific measure rather than a generic measure is preferred for the proper assessment of physical function in patients with extremity sarcoma. To date, several disease-specific questionnaires have already been developed to evaluate functional outcomes for patients undergoing surgery for extremity sarcomas (Davis et al. 1996; Enneking et al. 1993; Bekkering et al.
© 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Xu et al. SpringerPlus (2016) 5:1118
2009). Some examiner-dependent clinical measures such as range of motion and muscle strength or a combination of symptoms and mobility have been used. However, measures that reflect the patient’s perception seems more desirable in clinical practice. As a patient-completed questionnaire that takes into account the heterogeneity of sarcomas, the Toronto Extremity Salvage Score (TESS) was developed for assessing physical function of patients undergoing surgery for extremity sarcoma (Davis et al. 1996). The TESS questionnaire is a disease-specific and selfadministered questionnaire based on the definitions of disability, impairment, and handicap as documented by the World Health Organization (Davis et al. 1996). The content of the TESS includes the types of functional difficulties experienced by extremity sarcoma patients, such as body movement, mobility, self-care, and performing daily tasks. To date, several studies have reported the validation of the TESS in a Portuguese (Saraiva et al. 2008), Danish (Saebye et al. 2014), Korean (Kim et al. 2015) and Japanese version (Ogura et al. 2015), yielding good test– retest reliability and internal consistency. However, to the best of our knowledge, there is no study that addresses the application of TESS to patients from the Chinese population. Herein, this study was conducted to investigate the comprehensibility, reliability and validity of the Chinese version of TESS for use in patients with extremity sarcoma.
Methods Subjects recruitment
The protocol of recruitment of participants was approved by the ethics committee of the hospital. Patients who visited our clinic center between March 2011 and September 2014 were prospectively evaluated for the eligibility of recruitment in this study. The following inclusion criteria were used: (1) aged more than 18 years; (2) at least 1 year after curative surgery for histologically confirmed extremity sarcoma; (3) without local recurrence, distant metastasis or complications related to surgery. Finally, 64 patients including 35 male and 29 female participated in the study and gave their informed consent. Demographic data were collected from the medical records, including patients’ age, gender, location of the tumor, histological type, type of surgery and period of follow-up. Translation and adaptation of the TESS
The translation and adaptation processes of the TESS were performed according to the guidelines used by previous literatures (Saraiva et al. 2008; Kim et al. 2015; Ogura et al. 2015). The English version of the TESS was translated into Chinese independently by three native Chinese bilingual translators who were familiar with the
Page 2 of 6
topic and the research concept. Subsequently, the two translators with the medical background analyzed and compared the three translations together with two senior musculoskeletal oncologists, and then combined them into one single translation. The consensus version was back translated into English independently by two bilingual translators who were kept blind to the procedures of the forward translation. All versions of the translation were analyzed by the expert committee, which was comprised of the 5 translators, one methodologist, and 2 orthopedic surgeons (X.L. and W.S.). The committee evaluated conceptual equivalence of all items and answers, and discrepancies between members were discussed. The pre-final version of the TESS was created after consensus was reached among the expert committee. In the pre-test step, 40 volunteers aged more than 18 years were recruited from the local community to test the pre-final Chinese version of the TESS. These volunteers were questioned about their understanding of the questionnaire items. Most of the items in the questionnaire could be correctly understood and answered by the volunteers. There was a high incidence of “not applicable” with regard to the question on sexual activity, which was therefore omitted from the questionnaire. After this process, the final version of the Chinese version of the TESS was developed. It consists of a lower extremity and an upper extremity version both with 29 questions. Each question is rated on 5-point scale, including “impossible to do,” “extremely difficult,” “moderately difficult,” “a little bit difficult,” and “not at all difficult”. The participant can select “not applicable” when the question is not a usual activity. The total score ranges from 0 to 100, with higher scores indicating better function. Reliability and validity test of the TESS
All the patients were asked to answer the TESS questionnaire at their follow-up visit after surgery. The time needed for the completion of the questionnaire was recorded for each participant. To examine the test– retest reliability, patients were asked to complete the same TESS questionnaire 1 week later. All the patients returned the second questionnaire used for analysis. The data were collected by an author (S.W.) who was kept blind of the patients’ diagnosis or treatment. To examine the convergent validity, the patients were also asked to complete the Musculoskeletal Tumor Society (MSTS) Rating Scale, and the Quality of Life Questionnaire Core 30 of European Organization for Research and Treatment of Cancer (EORTC QLQ-C30). The MSTS Rating Scale is a widely used functional score for patients with extremity sarcoma (Rebolledo et al. 2013). It consists of factors pertinent to the patient, including pain, function, emotional acceptance, use of any external support,
Xu et al. SpringerPlus (2016) 5:1118
walking ability, and gait alteration. A value of 0–5 points (maximum overall score, 30 points) was assigned to each of these factors. The QLQ-C30 is a 30-item questionnaire used to evaluate the function and QoL in cancer patients (Fitzsimmons et al. 1999). The following scales among the functional scales of QLQ-C30 were used in this study, including physical functioning (PF), role functioning (RF), social functioning (SF) and QoL. A high score on the functional scales represents a high level of QoL and a high level of functionality.
Page 3 of 6
Table 1 Baseline characteristics of the patients Characteristic
Patients (n = 64)
Age (year)
47.5 ± 15.2
Gender Male
35
Female
29
Time from surgery (year)
1.9 ± 1.2
Tumor location Upper extremity Upper arm
12
Factor analysis
Shoulder
5
Confirmatory factor analysis was carried out with each factor being specified to load on its subscale. Model fit was assessed with the following parameters, including the comparative fit index (CFI), the normed fit index (NFI), root-mean square error of approximation (RMSEA), and the 90 % confidence intervals (CIs) of RMSEA. A good fit of the model was indicated by ratios between the Chi square test and degrees of freedom less than 3, CFI and NFI values not less than 0.90, and RMSEA not more than 0.08.
Forearm/wrist
4
Elbow
2
Statistical analysis
SPSS for Windows version 16.0 statistical software (SPSS, Chicago, IL, USA) was used for statistical analyses. Descriptive demographic data and scores were reported as mean values ± standard deviation. The test–retest reliability was examined using intra-class correlation coefficient (ICC). The internal consistency was evaluated by Cronbach’s α, with a value >0.70 considered acceptable. To determine the convergent validity of the TESS, correlations between similar domains of the TESS and the QLQ-C30 or the MSTS were analyzed by Pearson correlation analysis. The correlation coefficient larger than 0.40 was considered to indicate adequate convergent validity.
Results The mean time used to complete the TESS questionnaire was 285.2 ± 75.7 s (range 182–382). The baseline characteristics of the patients were summarized in Table 1. The mean age at the time of completion of the questionnaire was 47.5 ± 15.2 years (range 18–68 years). The most common histological types were osteosarcoma (n = 15) and chondrosarcoma (n = 13) for bone sarcoma and liposarcoma (n = 11) for soft tissue sarcoma. Most patients received limb salvage surgery followed by chemotherapy with a mean follow-up of 1.9 ± 1.2 years (range 1–3 years). Results of reliability evaluation for Chinese version of the TESS were summarized in Table 2. The ICC for the test–retest reliability was 0.932 for the upper extremity
Lower extremity Thigh
14
Lower leg
10
Pelvis/hip
7
Knee
6
Ankle/foot
4
Histological type Bone Osteosarcoma
15
Chondrosarcoma
13
Soft tissue Liposarcoma
11
Undifferentiated pleomorphic sarcoma
6
Myxofibrosarcoma
5
Fibrosarcoma
4
Leiomyosarcoma
3
Epithelioid
3
Others
4
Surgery type Amputation
11
Limb salvage
53
questionnaires (95 % confidence interval (CI) = 0.745– 0.971) and 0.893 for lower extremity questionnaires (95 %CI = 0.755–0.937), respectively. In addition, the test for internal consistency showed strong reliability with a Cronbach’s α of 0.953 for the lower extremity questionnaire and 0.921 for the upper extremity questionnaire. The Pearson correlation coefficients between one item and the total score ranged from 0.533 to 0.869 for the lower extremity questionnaire and from 0.587 to 0.913 for the upper extremity questionnaire. As shown in Table 3, the overall mean score of the TESS was 87.6 ± 20.2 (range 40–100). The mean scores of the lower extremity questionnaire and the upper extremity questionnaire were 83.4 (range 40–100) and 92.3 (range 45–100), respectively. The mean score of the MSTS was 24.6 (range 5–30). The mean score of the QLQ-C30 was
Xu et al. SpringerPlus (2016) 5:1118
Page 4 of 6
Table 2 Reliability test of the simplified Chinese version of the TESS The TESS
ICC (95 % CI)a
Cronbach’s α
Correlationb
Lower extremity
0.893 (0.755–0.937)
0.953
0.533–0.869
Upper extremity
0.932 (0.745–0.971)
0.921
0.587–0.913
Table 4 Convergent validity of the Chinese TESS
MSTS Physical functioning Role functioning
ICC indicates Intraclass correlation coefficient; 95 % CI indicates 95 % confidential interval
Correlations between one item and the total score excluding that item using Spearman rank correlation coefficient
MSTSb
0.682†
0.782†
0.735†
†
0.547†
†
0.532†
†
0.635†
0.712
Quality of life †
TESS
0.637†
0.638
Social functioning
b
a
Upper extremity (r)
QLQ-C30
a
Table 3 Patients’ score of the TESS, the MSTS and the QLQC30
Lower extremity (r)
0.689
p
